1. Field of the Invention
The present invention relates to a tubular label fitting apparatus that automatically fits a tubular label to a container such as a bottle.
2. Description of the Related Art
In the conventional and widely used application, a tubular label (referred to as simply “label” hereinafter) with heat shrinking properties is fitted to a container (referred to as simply “bottle” hereinafter) such as a synthetic resin bottle or glass bottle, and is then shrunk in order to mount a label to the bottle. Examples of a conventional label fitting apparatus are shown in Japanese Patent Application Laid-open No. 2000-289715, Japanese Patent Application Laid-open No. 2000-264319, and Japanese Patent Application Laid-open No. 2002-87417. The basic aspect of a conventional label fitting apparatus is shown in FIGS. 9 and 10, and comprises an infeed wheel 70, a main turret 71, a rotary vacuum transfer finger 72 and a discharge wheel 73, and as shown in FIG. 10 each head of the main turret comprises a bottle holder 78 that may open and close, a vacuum jaw 74 that holds a label by suction, a mandrel (pilot) 75 that moves vertically, and a label pusher 76 that presses a label down to a specified position on a bottle.
In the above apparatus, a label is mounted by the process shown in FIG. 10 in which a bottle supplied by an infeed wheel 70 is held by a bottle holder 78, and is conveyed in a circular motion along a guide mechanism 77 that is positioned on the outer fixed portion of the main turret. That is to say, a bottle holder 78 holds a bottle 30 and the main turret 71 rotates, thus reaching the label opening end position and the mandrel 75 begins to lower (process a), such that when the mandrel tip engages with the cap of the bottle 30 and determines the positioning, the bottle holder 74 opens. In this condition, the label pusher 76 lowers and presses down on the label to fit the label onto the bottle (process c), and the bottle holder re-closes when the label insertion is complete (processes d and e). When the bottle holder has completely closed (process e), the mandrel 75 and the label pusher 76 rise and return to the home position (process f). Upon reaching the position of the discharge wheel, the bottle holder opens and the bottle is transferred to the pocket of the discharge start wheel, and is conveyed to a shrink apparatus by a discharge conveyer, and the label 29 is heated so that the label 29 is shrunk and adheres to the outer face of the bottle.
As described above, the main turret in the conventional apparatus requires a bottle holder to grasp the bottle body and a fixed guide that is positioned on the outer fixed portion of the bottle conveyance path, such that a line change must be performed by changing the bottle holder and fixed guide according to the bottle size and differences in the bottle shape such as a round cross-sectional shape or square cross-sectional shape, which has the drawback of requiring considerable man-hours and labor to implement line changes each time a different bottle type is used. In addition, the conventional apparatus using the label holding means requires a label pusher to push down on the label held by the label holding means, in order to fit the label to the bottle in a stable manner. Furthermore, to ensure that the label fitting apparatus mounts the label on the bottle in the correct direction and correct position, caution is required to prevent misalignment of the label from when the label has been fitted until the bottle reaches the shrink oven, but the conventional apparatus has the drawback of easily resulting in misalignment of the label, in that the bottle that is fitted with a label is grasped from above, which causes the label to move when the bottle is grasped and when the holder opens.
On the other hand, when fitting a label 29 to a relatively small bottle 30 such as the 500 ml capacity bottle shown in FIG. 11-A, the label in most cases covers the entire body, whereas in the case of a 1-liter or 2-liter large capacity bottle 32 of the type shown in FIG. 11-B, the label frequently covers only the shoulder of the bottle 33. In this case, the label 29 becomes unstable and easily tilts to the side, such that when the label is not correctly engaged as shown in FIG. 11-C, the label is fitted while tilted to the side, and when the label is shrunk under the same condition the label becomes wrinkled as it shrinks, which has the drawback of resulting in a defective product, thus pointing to the need for a more accurate apparatus for fitting a label to a bottle.